Fluid pressure motor



July 29, 1952 R. R. STEVENS FLUID PRESSURE MOTOR Filed Jan. 3, 1948 Patented July 29, 1.952

VQ2,604,878 Y v FLUID `rltElssURii Mo'roR Roy R. vStevens,; Forest Hills, Pa., assignor to Y Westinghouse Air,l Brake tCompany, acorporation of Pennsylvania Application Januarys, 194s, serial No. '395 L1 claim.,V (c1. 121-38) if This invention relates to fluid pressure control .apparatus of `the type used for selectively controlling `multiple vposition clutches,t. gear changers etc. where definite positioning is `demanded. j .v Y :i

One object-of the invention is the provision of an improved lcontrol apparatus oftheabove wpa Y i Another object-of the inventionis the provision of ,an apparatus Yof the 'above'general type embodying lan -improved fluid pressure `'controlled positioning motor .andan improved manually-operated pressure controlling means therefor. f

In certain reversing clutches, as well as gear changers, the clutch Yengagement or Lge'archanger is A:maintained in a selected positionvafter'being so placed byspring action. through toggle mechanisms `in over dead-center positions-there'-v of, and also by quadrant and quadrant' riders,

etc. Power is therefore required'only'ior-moving the clutch or gear changer controlfsubstantially into a selected oneiof its diiierent positions and is Anot `required forA maintaining?the` clutch or gear changerin thas/elected position. v In many cases it is `not desirable Vvto maintain pressure on the clutch or gear changer controls in thatzit causes unduev wear tofthe shifting bear-I ings. i y

AAnother object of my invention is' therefore' the .provision of an improved power operated' positioning apparatus embodying a'multiple position-fluid pressure actuated power motorior selectively vpositioning a device such as athre'e position clutch or the like, and a-valve means embodying a plurality of individual lcontrol valve units, corresponding in number to the number of positions of the power motor,' each manually operative to supply -fluid under pressure'to' said: motor for eiiecting movement thereof-to "a'co'rresponding selected positionand' operabley tanto-i maticallyuupon release of manualpressure torelease Huid under pressure from said motor; K

Other objects and advantages `will'be apparent from the-following more detailedv 'descriptionof' the invention. A l In the 4accompanying drawing, vthe single 'figure' is a diagrammatic view vof a controlv apparatus embodying the invention." I

As shown in the drawing', the reference *inimeral I indicates la power 'motordevice for-positioning a three position clutch` control member 2, or the like, and the numeral`3 indicates a manually operative control valve device-for controlling-said power motor d'evice- I. Y Y The power motorl'devic'e comprises-:two -oping open` at adjacent ends ofsaid members and closedv atthe opposite ends. The casing members -4 and I5 are secured together --withV the bores 6 and :1 in coaxial relationship and with'. a gasket 8 sealing the joint therebetween. A

*A piston '9- slidably'niounted inthebore B Yof casing 4 is provided with an annular groove I0 in which is tted a suitable sealing ring vII having sliding and sealing engagement with the wall of saidbore; "I'hepiston `9 is solidly secured to one end of `a'piston rod VI2 which extends through alconcentrically arranged opening I3 in the closed'end wall of the 'bore 6. In the opposite oroute'rend 'of the piston' rod. I2 isa screwthreaded bore in' which is adjustably disposed the threaded end of yan 'eyebolt- I-4` which is adapted'to be connectedby apin" I5 to lthe 'device to belcontrolled-such, as the clutch-lever'Z' f which mavhave neutral, forward and reverse positions, as indicated by legends'on the drawlng 7,. i.,

Scuredlby a friction t in the casing bore` I3 is an annularmember lI B'havingan annular groove in'- its inner facein whichf' is located asealing ring I'I. This sealing *ringlll has asliding and sealing engagement with the' peripheral 'surface ofithe'piston rod I2 to preventfleakage vof iiuid pressurev from the bore l6 tothe atmosphere. The piston 9, the wall of bore 6,.the closed end of the casing!! and the member I6 together with thefseal II define achamberl which 'is open at all times'by Va pipe I9 to' the control valve device 3. Also included inthe bore I3 of casing 4 is a felt ring 26, a metal washer Ir anda vided with an annular groove vin vwhich Aa sealing ring`23, having sliding and sealing engagement with the wall of bore 1, is located. The piston 22 is further v'provided with a cylindrical extension member 24 which extends into "bo're of the casing'member 4 and therein terminates' in anannular shoulder 25 vwhich has a sliding nt in bores. Thisjextension 24 I and shoulder 25 form agnide member'forthe piston v22 `and also a stop member for piston 9 as will later be eX- plained. The closed end of casing 5, the wall of bore 1 and the face of piston 22 define a fluid pressure receiving chamber 26 which is open at all times by a pipe 21 to the control valve device 3.

The adjacent faces of pistons 9 and 22 and the walls of bores 6 and 1 dene a third chamber 28 between said pistons which is open at all times to the control valve device 3 by a pipe 29. Ports 30 in the extension 24 permit a continual equilization of pressures on all portions of piston 22 ad jacent chamber 28.

The operation of the power motor I is as (fol-' v lows: ,Y Y Upon supply of fluid pressure byepipeIS to chamber I8, while pipes 21 and 29 hence chambers 26 and 28 are open to the atmosphere, the piston e 9 will be moved by such uid in the direction of the left hand into engagement with the piston extension 24, and if the piston 22 is not already in engagementwith a shoulder. 22ccm theucasing 5 thepiston 9 will move pistonl 22y into such en-V gagement whereupon movement of piston 9 will be stoppedV by saidextensiongfor positioning the clutch control lever 2 in its reverseposition.

.The power motorI willA definitely position the clutch control lever 2 in theforward position defined by engagement ofpiston- 9 -with a shoulder 6a in the casingupon supply of fluid pressure by pipe 29 to chamber 28 while pipe I9 is open to the atmosphere, as will be apparent.

' This powermotor-devicewill denitely position the clutch control lever 2 in the neutral position, in which4 it is ,shownin `the drawing, upon supply of fluid pressure via pipes I9 and 21 to chambers I8 and 26respectively, while pipe 29 and `hence chamber 28 are open to the atmosphere. Thepressule. of fluidthusvprovided in chamber I8 and acting on piston 9 will urge said pistonagainst threiextension 24, while piston 22 being approximately twice the area of piston 9v the pressure of fluid in chamber 26 acting thereon will provide a force so Aexcaeeding the opposing force of piston-9 that even with-theclutch'control lever 2 in reverse position, the piston 22 will move both pistons againstpressure in chamber I8 until the piston 2 2 engagesthe open end of the casing Y4 in which positionit is shown in the drawing; vInfthisV position ofthe piston V22,the extension 24 will hold thejpiston 9 against pressure of fluid in chamber I8 in a neutral position for correspondinglyA positioning the clutch control lever 2. -g .l y A AThe control valvefdevice comprises a-casing 3I adapted-to be mounted-.on va suitable pannel 32 'or the like and containing a forward position valve unit 33, aY neutral position valve unit-34 and a reverse position vvalve unit 35. i v Y The three valve units 33, 34 and 35v are similar in construction` each comprising a cylindrical body portion '36 formedlwith a plurality of successively reducing diameters and inserted into a bore in the casing toaV position in which a shoulder 31 formed at the junction of a smaller diameter at one end and-an intermediate diameter engages asuitable shoulder 38 formed at the junction of two bores of different diameters in the casing. The larger end of the body 36 is provided with-a bore 29 in which is located a release valve 40 and a supplyvalve 4I. A smaller bore 42 extends from the-larger bore 29 through to the end of the smaller end of; the body portion. In this bore 42 is located a supply valve stem 43 one end of whichis vconnected to the supply valve. The supply valve stem extends beyond the valve body and is provided on its opposite end with a screw thread to receive a button 44 for manual operation of the valves as explained hereinafter.

A supply valve seat is formed on the body portion 36 around the end of bore 43 adjacent the bore 39 on which the supply valve is normally urged to seat and a number of small ports 45 extend from the bore 42 adjacent 'the supply valve seat to a port 46 in the casing 3I; which port is normally connected by a pipe 41 to a fluid pressure supply reservoir (not shown). The valve ,stem 43 is fluted adjacent the supply valve to allow flow of supply pressure past the supply valve `4I when-the valve is unseated and said stem is further provided with a sealing ring 48 in a cylindrical portion of said stem in sealing contact with the wall of the bore 42 which prevents leakage of fluid under pressure from the valve side of vsaid'rin'g to the atmosphere between the valve stem 43 and the bore 42. TheY release valve 40 comprisesa cup-shaped member 49 slidably mounted in bore 29 and a rubber like compositionL-.valveseat 50 'preferably vulcanized' to the inside ofv the cupfor coopera# tion with a valve seat to be hereinafter described. A spring 5I acting 'on the release .valve 48 l'normally supports it in an unseated position and' urges the contacting supply valve 4I against its seat.'

The larger openl end of the .casing bore containing the valve body 36 is normally closedby a member 52 disposed in said'bcre Withonesi'dein contact with the adjacent and larger'end of said body,.while engaging the opposite side is -a removable spring type snap ring. 53 a portion of which fits into an annular groove in'the casing open'to said bore. The ring 53 retains the valve bodyv 36 and the member 52 in the casing; but upon removal of said ring and of button 44, these partsmay be removed from the easing.VV 'An extension 54 of member 52 projects into .the bore 39 in the body 36 and on its end :thereis provided a' valve seat' for cooperation with the release valve 48. The spring 5I ,encirclesthe extension 54 andv is supportedvby the member 52;; -An-ex` haust port 55 leads from the release valve'seat to' the lower side of-themember 52 which-in the casing of valve units 33 and 34 isrexposedzto atmosphere. In valve unit 35 this port 55 leads to a chamber 56 formed between the lower` side. of member 52 and a closing member 5.1 held in the casing by a removable snap ring 51a. The member 51 is provided with a numberof lugs 58 which extend into contact with the member 52 of valve unit 35 to support saidvalve unit in the casing' 3 I'. In each of the valve units acavity 59 is formed i-n the casing 3I about the lower end` ofthebo'dy 36. This cavity 59 is connected to ach'amber 60 formed above the exhaust-valverMl and containing the supply valve 4I, byaV number of ports 6I1in the body. The cavity k59 isl also. lcon-A nected to achamber at theopposite side of` the release valve 40 by a number ofv small,` ports 62.1

The cavity 59 in valve unit 33 is connectedby a port 63 to pipe'29 leading to chamber 281m the power motor I. In the valve unit 34 Ycavity 59 is connectedby a port 64 to the Vcavity..56 in valve unit 35 and to pipe 21 leading to chamber 26 of the power motor I; In valve' unit 35 vcavity 59 is connected by a port 65 --to pipe I9 ,leading to chamber I8 of the power vmotor I.

Operation of apparatus to unseat the release valve v4l)l and to seat the supply valve4l. -Ch'ambers-28 and I8 in the motor` I will thereforebenormally openl to atmosphere past the open release -valves 4Q in the valve units 33, 34,. respectively, ,while chamber I8 in said motor will be op'e'n 'to atnflosphere past the open release valve 4ilin`ffthe valve .unit 35 an'd'thencethrough chamber55gzport 64 andp'ast th-opnf release valve v4l) in th'elvalve urit134- Now assuming that port 4'Iiiisconnectdtola suitable supply of iiuid under pressure, that the power motor l is positioned as shown in the drawing and that it is desired to effect movement of the clutch control lever 2 to its forward position. The operator will apply sufficient pressure to the button 44 of valve unit 33 to cause the supply valve 4I to be unseated and to seat the release valve 40 therein against the opposing force of the respective spring 5I. Fluid under pressure from the supply pipe 4l will then flow via port 46, and through the valve unit 33 via the respective ports 45, past the supply valve 4I, and ports 6I to cavity 59, and thence through port 63 and pipe 29 to chamber 28 of the power motor. With chamber I8 open to atmosphere as above explained, the pressure of fluid thus provided in chamber 28 will move piston 9 toward chamber I8 until it engages the closed end of casing 4 thus moving the clutch control lever 2 to its forward position. Fluid under pressure supplied to chamber 28 as just described will also move piston 22 to its outer position in contact with stop 22a but Without effect or importance in the operation under consideration. After the clutch control lever 2 obtains its forward position the operator can remove his hand from the button 44 of the valve unit 33, whereupon in said unit spring 5I will unseat the release valve 4l]V and seat the supply valve 4I. The supply of iiuid under pressure to chamber 28 will thereby be cut off and the iluid pressure in said chamber 28 will be released to the atmosphere past the unseated release valve 4B in valve unit 33 and through port 55, for thereby, in the case of a clutch or the like relieving the shifting bearings of actuating force.

To disengage the forward clutch by moving the lever 2 to neutral position, the operator will apply sucient pressure to the button 44 of valve unit 34 to cause it to move downward for unseating the supply valve 4I and seating the release valve 40 therein. Fluid pressure is thereby admitted to port 64 and thence through pipe 21 to chamber 26 of the power unit I and also from port 64 to chamber 56 of valve unit 35 and thence through port 55 past the unseated exhaust valve 4B of unit 35 ton port 65 therein which is open to chamber I 8 of the power unit I. Fluid under pressure thus supplied to chamber 26 will move piston 22 toward chamber 28 until it engages the open end of casing 4, while the uid under pressure provided in chamber I 8 will move piston 9 toward chamber 28 until it engages the extension 24 of piston 22 in which position it will stop due to the larger area of piston 22. The piston 9 as it thus moves will pull the clutch lever 2 to its neutral position. As soon as the clutch lever 2 obtains its neutral position the operator will remove pressure from button 44 of unit 34 to permit closing of the supply valve 4I and opening of the release valve 46 therein to permit release of fluid under pressure from piston chambers I3 and 26 in motor I for relieving the clutch control lever 2 of actuating force.

" "'I'o .move the-clutch control lever :2 to reverse' 28 carrying with it piston 22 until the piston 22 engages the closed end of casing 5 which limits the movement of piston 'I to a position in which the clutch lever 2 is in its reverse position. After the clutch lever 2 obtains its reverse position manual pressure is removed from the valve unit 35 to permit opening of the release valve 4D and closing of the supply valve 4I therein. The uid pressure in chamber I8 will then ilow past the release valve of unit 35 to chamber 56, then to port `64 and to the atmosphere past the unseated release valve of unit 34, for thereby relieving the clutch control lever 2 of actuating forces.

In order to return the clutch control lever 2 from reverse position to neutral position the button 44 of the valve unit 34 need only be depressed and then after the operation is completed said button may be released to relieve said lever of actuating force, as will be clear from previous description.

Summary From the above description it will now be seen that I have provided a control apparatus embodying a fluid motor for positively, selectively positioning a multi-position device in accordance with selective manual operation of any one of a plurality of control valve units, corresponding in number to the positions of said device, and which units are automatically operative upon relief of manual force at the termination of a selected operation to release actuating fluid under pressure from the motor for relieving the device of operating force.

Having now described my invention, whatvI claim as new and desire to secure by Letters Patent, is:

A fluid motor comprising two casing parts removably secured one to the other and having, respectively, tWo coaxially aligned bores open to each other at adjacent ends and closed at their opposite ends, one of said bores being larger in diameter and shorter than the other bore, a piston slidably mounted in each of said bores, the two pistons cooperating with each other to form a pressure chamber between them for receiving fluid under pressure to act on adjacent faces of said pistons for moving them apart into contact with the closed end walls of the respective bores, a second pressure chamber at the opposite face of the larger piston for receiving iluid under pressure to act on and move said larger piston into contact with the adjacent end of the casing part having the smaller bore, a third pressure chamber at the opposite face of the smaller piston for receiving iiuid under pressure to act on and move the smaller piston in the direction of the larger piston, a rod to be actuated connected -at one end to said smaller piston and projecting therefrom through said third pressure chamber 7 8 r and the closed end Wall of the smaller bore to the exterior ofsaid motor, a-cylindrical element of REFERENCES CITED- Smaller diameter than Said Smaller bore disposed The following references are of record in the in the rst named chamber and secured at one me of this patent; end to said larger piston with the opposite end 5 constantly disposed in the smallerbore for en UNITED' STATES PATENTS gagement by the` smaller piston, an annular Number Name Date shoulder on said opposite end of said cylindrical 1,144,758 Desmond June 29, 1915 element having sliding engagement with the Wall 2,095,820 Lenz Oct. 12, 1937 of said smaller bore, and a.- port through said 10 2,401,197 Simpson May 28, 1946 cylindrical element opening the exterior ftov the Y interior thereof. t y s f f I ROY R. STEVENS. v 

